1. Field of the Invention
This invention relates to a polyolefin composition with an improved weather resistance and more particularly, it is concerned with a polyolefin composition whose weather resistance, in particular, at high temperatures is improved by blending with weatherproofing agents in a specified combination.
2. Description of the Prior Art
Polyolefins are very useful for moldings, films, fibers, etc. because of their outstanding mechanical properties, but they tend to be degraded by ultraviolet rays when used outdoors. For the protection thereof from degradation by ultraviolet rays, it is well known to add thereto a stabilizer for weathering, for example, salicyclic acid esters, benzophenone, benzotriazole and nickel chelate compounds.
As polyolefins have lately found wider applications, it has become a popular practice to add synthetic rubbers, inorganic fillers, pigments, etc. for the purpose of improving their mechanical properties, performances and appearance of their moldings so that they meet requirements for the specific applications. The requirement for weather resistance has become more stringent than before and polyolefins are required to resist weathering at high temperatures. In particular, moldings produced from polyolefin compositions blended with these fillers or additives are used in fields where weather resistance is required, but inorganic fillers tend to lower the weather resistance of a polyolefin composition containing them, particularly, at high temperatures. Therefore, it has become ascertained that the above described stabilizers for weathering are not so effective when used in combination with inorganic fillers.